# Integer to Roman¶

## Question¶

Write a program which converts the given input integer to roman numeral.

## Solution¶

```# Program which converts the given input integer to roman numeral.
# Limitation: Program converts the integer numbers uptil the value of 1000
# (Roman Numeral: D)
# Problem: P2.1 - Implement a translator from integers to roman numeral based
# on the syntax directed translation scheme developed in Exercise 2.9
# Chapter 2 - A Simple One-Pass Compiler. Compilers, Principles, Techniques
# and Tools.

roman_dict = {1:'I',5:'V',10:'X',50:'L',100:'C',500:'D',1000:'M'}

def sep_num(n):
num = []
if n/100:
hundreds = (n/100) * 100
num.append(hundreds)
n = n%100
tens = (n/10) * 10
if tens:
num.append(tens)
ones = n%10
if ones:
num.append(ones)
elif n/10:
tens = (n/10) * 10
num.append(tens)
ones = n%10
if ones:
num.append(ones)
else:
ones = n
num.append(ones)
return num

def get_roman(n):
rnos = []
if n in roman_dict:
rnos.append(n)
return rnos
else:
if 1 < n < 5:
base,factor = 1,1
rnos.append(base)
result = n - base
while result > 0:
rnos.append(factor)
result = result - factor
if rnos.count(factor) > 3:
for n in rnos[:]:
rnos.remove(n)
indices = list(roman_dict.keys())
indices.sort()
prev_base = base
base_index = indices.index(base) + 1
base = indices[base_index]
rnos.append(prev_base)
rnos.append(base)
return rnos
elif 5 < n < 10:
base,factor = 5,1
rnos.append(base)
result = n - base
while result > 0:
rnos.append(factor)
result = result - factor
if rnos.count(factor) > 3:
for n in rnos[:]:
rnos.remove(n)
indices = list(roman_dict.keys())
indices.sort()
prev_base_index = indices.index(base) - 1
prev_base = indices[prev_base_index]
base_index = indices.index(base) + 1
base = indices[base_index]
rnos.append(prev_base)
rnos.append(base)
return rnos
elif 10 < n <50:
base,factor = 10,10
rnos.append(base)
result = n - base
while result > 0:
rnos.append(factor)
result = result - factor
if rnos.count(factor) > 3:
for n in rnos[:]:
rnos.remove(n)
indices = list(roman_dict.keys())
indices.sort()
prev_base = base
base_index = indices.index(base) + 1
base = indices[base_index]
rnos.append(prev_base)
rnos.append(base)
return rnos
elif 50 < n < 100:
base, factor = 50,10
rnos.append(base)
result = n - base
while result > 0:
rnos.append(factor)
result = result - factor
if rnos.count(factor) > 3:
for n in rnos[:]:
rnos.remove(n)
indices = list(roman_dict.keys())
indices.sort()
prev_base_index = indices.index(base) - 1
prev_base = indices[prev_base_index]
base_index = indices.index(base) + 1
base = indices[base_index]
rnos.append(prev_base)
rnos.append(base)
return rnos
elif 100 < n < 500:
base, factor = 100, 100
rnos.append(base)
result = n - base
while result > 0:
rnos.append(factor)
result = result - factor
if rnos.count(factor) > 3:
for n in rnos[:]:
rnos.remove(n)
indices = list(roman_dict.keys())
indices.sort()
prev_base = base
base_index = indices.index(base) + 1
base = indices[base_index]
rnos.append(prev_base)
rnos.append(base)
return rnos
elif 500 < n < 1000:
base, factor = 500, 100
rnos.append(base)
result = n - base
while result > 0:
rnos.append(factor)
result = result - factor
if rnos.count(factor) > 3:
for n in rnos[:]:
rnos.remove(n)
indices = list(roman_dict.keys())
indices.sort()
prev_base_index = indices.index(base) - 1
prev_base = indices[prev_base_index]
base_index = indices.index(base) + 1
base = indices[base_index]
rnos.append(prev_base)
rnos.append(base)
return rnos

def main():
number = int(input("Enter the Integer: "))
if number > 1000:
print('Sorry, I know uptil 1000 only.')
exit()
if number in roman_dict:
print("Roman: ",roman_dict[number])
else:
romans = []
res = sep_num(number)
for each in res:
rvalues = get_roman(each)
for value in rvalues:
romans.append(roman_dict[value])
print("Roman: ",''.join(romans))

if __name__ == '__main__':
main()
```